Charles Inglis (engineer)

Charles Edward Inglis
Born	31 July 1875 Worcester
Died	19 April 1952
Nationality	British
Education	Cheltenham College & King's College, Cambridge
Spouse	Eleanor Moffatt
Children	Two daughters
Parents	Dr Alexander Inglis & Mrs Florence Inglis
Work
Engineering discipline	Civil, Mechanical, Structural
Institution memberships	Institution of Civil Engineers (president), Institution of Mechanical Engineers (honorary member), Institution of Naval Architects (council member), Institution of Structural Engineers (council member), Institution of Waterworks Engineers (council member)

Sir Charles Edward Inglis OBE (pronounced Ingels) (31 July 1875 – 19 April 1952) was a British civil engineer. Inglis spent much of his life as a lecturer and academic at the King's College of Cambridge University and made several important studies into the effects of vibration and defects on the strength of plate steel. Inglis served in the Royal Engineers during the First World War and invented a the Inglis Bridge, a reusable steel bridging system – the precursor to the more famous Bailey bridge of the Second World War. His military service was rewarded with an appointment as an Officer of the Order of the British Empire.

He was involved in the Institution of Naval Architects, Institution of Civil Engineers, Institution of Mechanical Engineers, Institution of Structural Engineers, Institution of Waterworks Engineers and the British Waterworks Association, sat on several of their councils and was elected as president of the Institution of Civil Engineers for the 1941-2 session. He also sat on the board of inquiry looking into the loss of airship R101 and was chair of a Ministry of War Transport railway modernisation committee in 1946.

Early life and career

Charles Inglis was the second son of Dr Alexander Inglis, a general practitioner in Worcester, and his first wife, Florence, who was the daughter of newspaper proprietor John Frederick Feeney. Charles was born on 31 July 1875 and was not expected to survive, being hurriedly baptised in his father's drawing room, with his mother dying from complications eleven days later. His family moved to Cheltenham and Inglis was schooled at Cheltenham College from 1889 to 1894, in his final year he was elected head boy and received a scholarship to study the Mathematics Tripos at King's College, Cambridge. Inglis was 22nd wrangler when he received his Bachelor of Arts degree in 1897 and remained for a fourth year, achieving first class honours in Mechanical Sciences. Inglis was a keen sportsman and enjoyed long distance running, walking, mountaineering and sailing, at Cambridge he nearly achieved a blue for long distance running but was forced to withdraw from a significant race with a pulled muscle.

After graduation Inglis began work as an apprentice for the civil engineering firm of John Wolfe-Barry & Partners. He worked a draughtsman in the drawing office for several months before being placed with Alexander Gibb, who was acting as resident engineer on an extension to the Metropolitan Line between Whitechapel and Bow. Inglis was responsible for the design and supervision of all nine bridges on the route. It was during this time that he began his lifelong study of vibration and its effects on materials, particularly bridges.

Early academic career

In 1901 Inglis was made a fellow of King's College after writing a thesis entitled The Balancing of Engines, the first general treatment of the subject which was becoming increasingly important due to the growing speeds of locomotives. In the same year he received his Master of Arts degree and was accepted as an associate member of the Institution of Civil Engineers (ICE) after winning the institution's Miller Prize for his student paper on "The Geometrical Methods in investigating Mechanical Problems". Inglis left his employment with Wolfe-Barry and returned to King's College, becoming an assistant to James Alfred Ewing, professor of mechanism and applied mechanics. Ewing left the university in 1903 to become the first Director of Naval Education at the Admiralty but Inglis remained, being appointed lecturer in mechanical engineering by Professor Bertram Hopkinson and working with him to study the effects of vibration. Hopkinson recognised his abilities as a lecturer and assigned him the heaviest teaching load of all the staff, covering statics, dynamics, structural engineering theory, materials engineering, drawing, engine balance, girder design and reinforced concrete.

Inglis had married Eleanor Moffat, daughter of Lieutenant-Colonel Herbert Moffat of the South Wales Borderers, in 1901 with whom he would have two daughters. He lived in Cambridge until 1904 when he built a house at Grantchester, where he and his family resided until 1925. In 1913 he published a paper on the stress caused to plates by defects which has been described as his most important contribution to engineering. Alan Arnold Griffith based much of his work on the apparent discrepancy between calculated and actual strengths of materials upon Inglis' paper.

Military service

A surviving Inglis Bridge over the River Monnow

Inglis was involved with the Cambridge University Officer Training Corps (CUOTC), being commissioned a second lieutenant on 24 May 1909. He served with the engineering detachment of the CUOTC and noticed that when the unit was deployed on field days with the rest of the force it often had little to do. To remedy this Inglis designed a reusable steel bridge with the intention that it could be erected and dismantled by the unit in a single afternoon. An army general who was inspecting the unit noticed his design and offered advice that "If you're making anything for the army, keep it simple – no complicated gadgets". Upon the outbreak of war Inglis volunteered for active service in the British Army and was officially listed as an Assistant Instructor in the School of Military Engineering, with the temporary rank of lieutenant. The army expressed interest in Inglis' bridge design and it was approved for use by a panel of army officers that included the general who had first commented upon the design and to whom Inglis said "I hope, Sir, you will find I have profited by your advice". The design, composed of a series of triangular truss sections was highly successful, still being in use by the start of the Second World War and influencing Sir Donald Bailey who designed the Bailey Bridge as a higher capacity replacement.

In 1916 Inglis was placed in charge of bridge design and supply at the War Office. In this role he received promotion to the rank of captain on 6 May 1916 and became a Staff Captain attached to the War Office on 26 June 1917., At the war's end in 1918 he retired with the rank of major and was rewarded for his service with appointment as an Officer of the Order of the British Empire. In addition to his bridge design he also developed the Inglis Tubular Observation Tower during teh course of the war.

Return to King's College

Telford Medal of the Institution of Civil Engineers such as that awarded to Inglis in 1924

Inglis returned to Cambridge in 1919 and was appointed professor of Mechanism and Applied Mechanics (in 1934 this was renamed to Mechanical Sciences). On 25 March 1919 he was selected as head of the Cambridge University Engineering Department as the successor of Hopkinson, who had died in an air crash the previous year. Though he made no radical changes to the department, such as had occurred under his predecessors Ewing and Hopkinson, under Inglis' supervision the department became the largest in the university and one of the best engineering schools in the world. Frank Whittle, who was later knighted for his work developing the jet engine, was one of Inglis' students in the department.

From 1923 he was involved with the analysis of vibration and its effect on railway bridges for British Railways, including a period spent working with Christopher Hinton during the latter's final year at Cambridge. Inglis was elected a member of the ICE in 1923 and became a member of its council in 1928, he was very active professionally and also served on the councils of the Institution of Naval Architects, Institution of Structural Engineers and the Institution of Waterworks Engineers. He was also an honorary member of the Institution of Mechanical Engineers.

Inglis was a prolific writer, publishing 25 books and academic papers on a wide range of engineering topics. He received the ICE's Telford Medal for a paper entitled The Theory of Transverse Oscillations in Girders and its Relation to Live Load and Impact Allowance in 1924. In 1926 he was 1926 he was appointed to a Royal Commission considering cross-river traffic in London. Inglis founded the Cambridge Engineers' Association to promote social activities at the University and saw Sir Charles Parsons appointed as its first president. In the same year he was awarded the honorary degree of Doctor of Laws by the University of Edinburgh.

Wreckage of the R101 airship, the loss of which was investigated by Inglis

In 1930 he was appointed to the board of inquiry looking into the loss of the airship R101 and in the same year was made a Fellow of the Royal Society. Inglis was a member of the London, Midland and Scottish Railway's Advisory Committee on Scientific Research from 1931 to 1947 and conducted numerous experiments on their behalf in the laboratories at Cambridge. He published A mathematical treatise on vibrations in railway bridges in 1934 and also submitted several papers on the matter to the Institution of Civil Engineers. Inglis delivered the Trevithick Memorial Lecture for the ICE in 1933 and was elected president of the British Waterworks Association in 1935. At around this time he was appointed to the governing council of Cheltenham College, if which he remained a member for the rest of his life.

He was due to retire from the university in 1940 but was persuaded to remain for another three years so that John Baker could be appointed in his stead. Inglis was elected president of the ICE for the 1941-2 session, having been vice-president in 1938. In his inaugural presidential address he stated that "the soul and spirit of education is that habit of mind which remains when a student has completely forgotten everything he has ever been taught". He delivered the Thomas Hawksley Lecture on "Gyroscopic Principles and Applications" for the Institution of Mechanical Engineers in 1943 and the fiftieth ICE James Forrest lecture on "Mechanical Vibrations, their Cause and Prevention" in 1944, being awarded the ICE's Charles Parsons medal the same year.

After his retirement as head of department Inglis served as Vice-Provost of King's College from 1943 to 1947. He received a knighthood in the 1945 King's Birthday Honours and in 1946 was appointed chair of the committee charged with advising the Minister of Transport on railway modernisation. He published the textbook Applied mechanics for engineers in 1951 following which he spent three months as a visiting professor at the University of Witwatersrand in South Africa. His wife, Eleanor Inglis, died on 1 April 1952 and Charles himself died eighteen days later. The Inglis Building of the Cambridge University Engineering Department is named in his honour.

References

Professional and academic associations
Preceded by Leopold Halliday Savile	President of the Institution of Civil Engineers November 1941 – November 1942	Succeeded by John Edward Thornycroft